Method and device for the needle-free injecting of fluid into a substrate, and fluid container for use in the method and the device

ABSTRACT

The invention proposes a method and a device for needleless injection of liquid into a substrate, in particular of a liquid pharmaceutical or cosmetic preparation into a biological tissue, making it possible in a particularly advantageous manner to reliably inject a liquid completely into the substrate without a needle. In accordance with the invention, this is achieved by a sequential injection, wherein a first partial quantity of the liquid first exits from an outlet nozzle at a very high outlet velocity as a fine liquid jet under high pressure generated in the liquid by means of a impulse shock and enters the substrate and creates an injection channel in the substrate, into which a second partial quantity of the liquid is then introduced at lower pressure and lower velocity. Preferably, the ejected liquid jet is set in rotation around its jet axis before it impinges on the substrate, so that the jet receives a helical movement and thus practically drills into the substrate without splashing away laterally.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 U.S. National Phase of International Application No. PCT/IB2018/058812, filed on Nov. 9, 2018, which claims the benefit of German Patent Application No. 10 2017 126 493.0, filed on Nov. 10, 2017. The entire disclosures of the above applications are incorporated herein by reference.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Technical Field

The invention relates to a method for needleless injection of liquid into a substrate, in particular a liquid pharmaceutical or cosmetic product into a biological tissue. The invention further relates to an injection device for needleless injection of liquid into a substrate, in particular of a liquid pharmaceutical or cosmetic product into a biological tissue, comprising a liquid supply, an outlet nozzle and an ejector device ejecting liquid in the form of a liquid jet from the supply through the outlet nozzle. Finally, the invention also relates to a liquid container for use in carrying out the method according to the invention and/or in the device according to the invention.

Discussion

To inject a liquid into a substrate, for example a liquid pharmaceutical or cosmetic product into or under the skin of a human or other living being, the liquid is usually injected through an injection needle into the substrate, i.e. the human or animal tissue. For this, the injection needle must first penetrate into the substrate. As a result of the incision made by a cutting edge at the needle tip, injuries occur which, although they usually heal quickly in living tissue, regularly result in scar formation. Furthermore, injections with injection needles always carry the risk of infection.

There have therefore been various experiments in the past with hypodermic jet injection devices for needleless injection to bring a small amount of liquid, such as a vaccine or other drug, an anesthetic or the like, directly through the skin surface into the tissue while forgoing the use of an injection needle that can penetrate into the substrate. Basically, the idea behind these efforts was to penetrate the patient's skin solely by the pressure of the liquid and to bring the injection medium to a desired depth. However, the devices developed for this purpose were not able to fulfill the expectations placed on them.

The injection devices proposed in the past for needleless injection of liquids such as drugs have an energy storage such as a spring mechanism, a pressure reservoir and/or a detonator which, when triggered, causes a pressure increase in a liquid supply contained in the device in order to eject liquid from the supply through an outlet nozzle. The nozzle cross-section is as small as possible and the pressure acting on the liquid supply is as high as possible in order to produce a liquid jet with a small cross-section and high jet velocity.

From US 2002/0143323 A1 an endoscopic device for gastrointestinal epithelial removal is known, in which a probe is supplied with a liquid. The liquid is supplied to the probe from a supply container which can be acted on by a pressurized gas from a gas bottle. US 2006/0149193 A1 discloses a device with a probe and a liquid applicator, which has a liquid outlet for needleless injection of a liquid into a biological tissue and a liquid conduit leading to the liquid outlet. An associated liquid delivery device has a drive device and is connectable to a pressure storage pressure container as energy storage. The liquid delivery device includes an expansion chamber which has a movable wall surface which encloses the liquid to be injected and which can be acted upon by a pressurized liquid.

Furthermore, devices are known which are used for needleless injection of a liquid under the mucosa. For example, US 2009/0157114 A1 discloses an endoscope with a probe for needleless injection under the mucosa. For this purpose, the probe emits a jet of a sodium chloride solution, which penetrates the tissue due to its small cross-section and concurrently high velocity. A pump unit or, optionally, a force-enhancing lever is provided to convey the sodium chloride solution and generate the respective pressure.

The known devices have so far proved to be little successful, because the liquid jet produced by them breaks up immediately after exiting the outlet nozzle and concurrently reduces its velocity. When it impinges on the substrate, it then tends to “mushroom”, i.e. splash apart, so that at least some of the liquid directed at the substrate surface does not penetrate the substrate, but is drained off sideways from the point of impact. As a result, it is unclear whether and how much liquid was actually injected into the substrate. With the known devices it is in particular not possible to bring liquid to a desired depth in the substrate and to create a liquid depot with a certain amount of liquid at this depth.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The aspect of the invention is therefore to provide a method and a device of the aforementioned type, which enables a reliable injection of liquid into a substrate without the use of an injection needle (cannula) pierced into the substrate.

This aspect is achieved with the method according to the invention in that a pre-jet is generated by means of a first partial quantity of liquid exiting the outlet nozzle at high velocity, which pre-jet forms an injection channel in the substrate, and that subsequently at least a second partial quantity of liquid is passed into the substrate through the injection channel generated by the pre-jet. The device according to the invention is characterized in that the ejector device has means for generating an impulse shock acting at least on a first quantity of liquid in the liquid supply.

With the method and device according to the invention, a first partial quantity of liquid is first ejected from the outlet nozzle at very high velocity as a fine liquid jet with a small cross-section. For this purpose, it is possible that at least in the first partial quantity of liquid, an impulse shock (pressure shock) is generated which causes this first partial quantity to exit the device as a pre-jet at very high velocity as a result of the liquid pressure suddenly rising to a very high value and to impinge on the substrate and, with suitable selection of an ejection nozzle provided on the device, to penetrate into the substrate to a desired depth without significant resistance due to the then very small jet diameter. It is also possible to provide the high energy for the generation of the fine liquid jet with a high outlet velocity from the outlet nozzle in that the liquid in the injection device is first accelerated to an initial velocity with a liquid container containing it and then, at the end of the acceleration section, while the liquid container is decelerated at a stop, the liquid at least partly continues its movement through the outlet nozzle. In this advantageous procedure, a dynamic pressure component is applied to the liquid by the acceleration in the injection device, and the static pressure increase (impulse shock) in the liquid is correspondingly smaller when the liquid container is decelerated again after the acceleration and the liquid is pushed out of the container through the outlet nozzle.

The penetration depth of the liquid jet leaving the outlet nozzle into the tissue depends—besides its jet diameter—on the initial velocity of the liquid (dynamic pressure component) to which it is accelerated in the device and the strength of the impulse (static pressure component) exerted on the liquid, in particular the first partial quantity. Preferably, the liquid or the first partial quantity in the device, respectively, is initially contained in an accommodation space for the liquid supply and is in any case limited at an area by a shock inducer element for inducing the impulse shock. The shock inducer element, which can generally be any kind of means or design of the liquid supply or its accommodation space, respectively, which allows a pressure shock (impulse shock) to be introduced into the liquid contained in the accommodation space, can be acted upon by an actuating means of the ejector device, in particular an ejector plunger, which is provided for this purpose and which is accelerated to high speed after the device is triggered. When the actuating means hits the shock element of the liquid container/accommodation space, or in the embodiment, in which it is accelerated together with the liquid contained therein and the ejector plunger jointly to a velocity, when the liquid container hits the stop provided for this purpose in the housing, respectively, the shock impulse inherent in the actuating means due to its mass and its high velocity is transferred to the liquid contained in the accommodating space and causes a sudden, very large increase of pressure (pressure shock) in the liquid, which results in a first partial quantity of the liquid contained in the supply being ejected at a correspondingly high pressure. When ejection is made through a nozzle with a small cross section, this leads to a very high exit velocity of the liquid jet of the ejected first partial quantity at the nozzle outlet, where ambient pressure is then imposed on the liquid. The first partial quantity ejected as a result of the pressure shock thus exits the outlet nozzle at a very high speed, corresponding to the very high pressure briefly generated in the liquid, as a liquid jet—in a preferred embodiment as a liquid jet rotating around its jet axis—and penetrates the substrate without any further significant resistance. In the substrate, the liquid jet creates an injection channel which is open at the substrate surface and extends to an injection depth. This reached depth depends essentially on the jet velocity at which the first subset impinges on the substrate surface as well as on the jet thickness, which essentially results from the cross-section of the outlet nozzle through which the liquid exits the device. The velocity of the jet, in turn, is a function (among others) of the pressure that is actually achieved in the liquid only for a very short time as a result of the impulse shock. By varying the velocity of the actuating means (ejector plunger) and thus the amount of the impulse given to it, the injection or penetration depth into the substrate can be adjusted. Surprisingly, it has been found that also a second partial quantity of liquid, which is subsequently ejected from the nozzle of the device, penetrates without any problems into the injection channel into the substrate previously created by means of the first partial quantity, even if it is ejected through the outlet nozzle at a significantly lower pressure and accordingly impinges on the substrate at low velocity. This second partial quantity then enters without further resistance at the substrate surface into the previously created injection channel open at the substrate surface, up to the end of the channel, i.e. up to the penetration depth where the liquid is then distributed essentially evenly around the channel. A second partial quantity of the liquid can thus be injected to the desired depth in the manner of a liquid depot.

For carrying out such a two- or multi-stage injection, an ejector device with electromagnetic drive for the ejector plunger has proved particularly suitable. The ejector plunger is first accelerated by the electromagnetic drive in an acceleration section in front of the liquid container (or together with it) to the desired high plunger velocity and then in a very short time interval, optionally abruptly, decelerated (optionally together with the liquid container) to generate the impulse shock in the liquid, whereupon the pressure in the liquid suddenly rises to a very high value as described and the first partial quantity of liquid is ejected from the container and leaves the outlet nozzle at a very high velocity, preferably under rotation, i.e. a helical movement. For injecting a second (and possible further) partial quantity into the injection channel thus created by means of the first partial quantity, the ejector plunger is inserted by means of the electromagnetic drive in the manner of a syringe plunger of an injection syringe with an ejection force at the shock inducer element into the volume of the liquid accommodated in the liquid supply and thereby expels the liquid through the outlet nozzle, from where it enters the injection channel previously shot into the substrate by the first partial quantity. The liquid supply can therefore preferably be acted upon by means of an ejector piston which can be actuated by the ejection device, which ejector piston in turn can be acted upon by the ejector plunger or is formed by it.

The electromagnetic drive may be located at a rear end of the housing spaced from the outlet nozzle or a stop for the liquid supply or ejector plunger, respectively, or approximately in the middle of the housing, wherein the acceleration section extends between the outlet nozzle or stop, respectively, and the rear end of the housing.

The arrangement may be such that the electromagnetic drive has a magnetic coil formed on the ejector plunger itself as well as an iron cylinder and/or a stator coil surrounding the ejector plunger. The ejector plunger may be provided with an electric power storage device to supply the electromagnetic drive with electric power. Of course, it is also possible to provide an external electric power supply to supply the device with energy.

When the acceleration section in the area in front of and/or behind the ejector plunger is connected to pressure compensation openings, an influence of air compression or a resulting negative pressure, respectively, in the acceleration section on the movement of the ejector plunger is largely prevented. It is possible that the pressure compensation openings are connected to each other via an overflow line so that the air on the path in front of the ejector plunger can flow through the overflow line behind the plunger and thus ensure particularly reliable, rapid pressure compensation.

As already mentioned, in an advantageous embodiment of the invention, the ejector device comprises means for generating an increase in pressure in the liquid supply immediately following the exerted impulse shock, which means are expediently formed substantially by the ejector plunger which, after exerting the impulse shock, acts on the liquid supply by means of a force-exerting drive. The force-exerting drive is preferably the electromagnetic drive. When the liquid supply is accommodated in a liquid container which can be arranged replaceably in the housing, the outlet nozzle can be arranged on the liquid container, thus ensuring in any case that the most suitable outlet nozzle is used for a specific liquid to be injected.

Surprisingly, it has been found that a widening, i.e. an increase in cross-section, of the liquid jet on its way from the injection device to the substrate surface and the mushrooming repeatedly observed with the known devices when impinging on the substrate is very reliably avoided if the liquid jet rotates around its own axis (jet axis) when impinging on the substrate with preferably high jet velocity and small jet cross-section. It is assumed that centripetal forces acting as a result of the rotation hold the liquid particles (molecules) together, not only on the path of the liquid jet from the outlet nozzle to the substrate surface, but also when penetrating the substrate. In fact it seems that, at least if the outlet nozzle is suitably designed, the rotation of the jet after its exit from the outlet nozzle even leads to a reduction of the cross-section and thus to an increase in the velocity of the liquid jet, so that the liquid jet can impinge on the substrate even at a higher velocity than it has when exiting an outlet nozzle. Experiments have shown that the liquid jet reliably penetrates biological tissue such as the skin of a human or animal when injecting, even if the outlet nozzle of the device according to the invention is positioned at a distance from the tissue surface, i.e. the liquid jet has to bridge the distance between the nozzle and the tissue surface as a “free jet”, without an increase in the distance having a negative effect on the injection quality. The rotation, which is imposed on the jet before it impinges on the substrate, is superimposed on the translatory movement of the liquid in its jet direction to form a helical movement, with which, according to the observations made, the jet practically “drills” or “screws” itself into the substrate with very low resistance at the surface of the substrate, forming an inlet channel corresponding to the jet cross-section, wherein in fact practically none of the liquid impinging on the substrate is lost, i.e. does not penetrate into the substrate. Preferably, at least the first partial quantity of liquid is set in rotation about its jet axis before and during its passage through the outlet nozzle of the device according to the invention.

In an advantageous embodiment of the invention, the rotation of the liquid jet can be caused by means of at least one orifice plate or nozzle with at least one screw-shaped or helical fluid channel. Accordingly, the injection device according to the invention can preferably comprise at least one approximately screw-shaped or helical fluid channel at the outlet nozzle as a means of setting the liquid jet in rotation. With the aid of the at least one screw-shaped or helical fluid channel, the desired rotational movement is firstly applied at least to the first partial flow formed by the first quantity of the liquid flowing through the outlet nozzle at least at the outer circumference of the liquid jet, i.e. in the boundary region to the surrounding air, wherein this rotational or screw movement is transmitted into the interior of the liquid jet. It is also possible for the rotation of the liquid jet to be caused by means of a rotating orifice plate or nozzle, for which purpose the means provided by the device preferably comprise at least one rotationally drivable part of the outlet nozzle. A combination of the two rotation-generating measures is also conceivable. It is also possible, in case of a joint acceleration of the ejector plunger and the liquid supply containing the liquid, to simultaneously set these two components of the device, which are moved longitudinally along the acceleration section, in rotation about their longitudinal axis, so that the liquid contained in the supply is already swirling/rotating when the liquid supply hits the stop and maintains this angular momentum (swirling) when ejected through the outlet nozzle.

The injection device according to the invention may preferably be configured in such a way that the liquid supply, the outlet nozzle and the ejector device are arranged/arrangeable in a common housing. In this way, the device can be designed in a particularly compact way, for example the device is easily operable with only one hand as an injection device for injecting cosmetic or pharmaceutical liquids into or under the skin of a human or animal.

In an advantageous embodiment of the injection device, the at least one screw-shaped or helical fluid channel can be arranged at a nozzle wall limiting a passage in the outlet nozzle. For the injection device, the arrangement may be such that the outlet nozzle has at least one converging section whose cross-section decreases in the flow direction of the ejected liquid, so that the liquid is accelerated on its path through the converging section of the outlet nozzle. In this case it has been found to be advantageous when the at least one fluid channel extends over at least a partial length of the converging section.

The outlet nozzle can also have at least one section of constant cross-section, wherein the at least one fluid channel then preferably (also) extends at least over a partial length of the section of constant cross-section.

A particularly effective measure for imposing the desired rotational or screwing movement on the liquid flowing through the outlet nozzle consists in several fluid channels arranged essentially rotationally symmetrically to the axis of the liquid jet in the outlet nozzle. The plurality of fluid channels provides a comparatively large, screw-shaped or helical contact or interaction surface between the nozzle passage and the liquid flowing through it, whereby a strong swirl or a comparatively fast rotation of the liquid at the nozzle outlet can be achieved already for a short axial extension of the nozzle (nozzle length). The fluid channels can be arranged adjacent to each other on the passage wall which limits the passage of the outlet nozzle.

Another particularly advantageous embodiment is that the at least one fluid channel extends through the outlet nozzle in the form of a helical pipe from the inlet side to the outlet side of the outlet nozzle. In this embodiment, the rotational component of movement, which the liquid jet has after its passage through the outlet nozzle, is caused by the helical shape of the pipe through which at least a partial flow of liquid flows and is set in rotation about the axis of its streamline inside the pipe due to the different radii on the inside and outside of the pipe helix. When the pipe additionally has a helical radius decreasing from the inlet side to the outlet side, this leads in an extraordinarily advantageous way to a cyclone effect, namely to an increase in the flow velocity of the (rotating) liquid jet when it exits from the outlet nozzle formed in this way. A nozzle configured in this way can therefore be called a cyclone nozzle. The described effect can be further enhanced by providing two or more helical pipes, each offset at an angle to each other in the manner of a double helix or multiple helix. The effect of such a “cyclone nozzle” can also be achieved with one or more helical fluid channels arranged on the passage wall of a nozzle with a narrowing, in particular conical nozzle passage and on the wall of the latter.

An equally expedient embodiment is when the outlet nozzle has a central, preferably straight passage for a partial flow of the liquid and when the at least one fluid channel helically coaxially surrounds the central passage. A (second) partial flow then flows through the fluid channel particularly helically surrounding the central passage and in doing so is imposed with a helical movement as described above before it combines with the (first) partial flow after leaving the nozzle and transfers its rotational or helical movement into the latter so that the entire liquid flow consisting of both partial flows rotates about its jet axis in an advantageous manner according to the invention, while it impinges from the nozzle on the substrate and practically screws or drills itself into the latter.

As already indicated, the outlet nozzle can be rotatably mounted and can be set in rotation by means of a drive. In this case it preferably has at least one, in particular preferably several fluid channel(s) arranged eccentrically to the axis of the fluid jet ejected from the outlet nozzle. The rotational movement of the outlet nozzle or of the fluid channel(s) arranged therein, respectively, about the axis of the liquid jet transfers its rotational movement to the latter, so that the liquid jet has the rotational movement according to the invention about its jet axis when it exits the nozzle.

An embodiment which is particularly expedient from the point of view of manufacturing results when the outlet nozzle has a plurality of orifice plates arranged one behind the other in the flow direction of the liquid in form of an orifice plate stack, each of which has a slot opening extending over a part of the plate diameter, the slot openings of orifice plates succeeding one another in the orifice plate stack being arranged offset to one another by an angular amount in the circumferential direction. The orifice plates stacked one above the other with the slot openings arranged therein and aligned offset by an angular amount then form a central passage running essentially straight in the axial direction of the nozzle as well as two helically staircase-like stepped fluid channels arranged in the manner of a double helix along the forming wall of the central passage. The arrangement is preferably such that the amount of the offset in the circumferential direction at the radially outer ends of the slot openings is smaller than the width of the slot openings, so that the helical (staircase)-shaped effect of the fluid channels helically surrounding the central passage is ensured up to their radially outermost edge regions.

It is particularly advantageous for the use of the injection device as a cosmetic and/or pharmaceutical device, when the liquid supply is formed by a liquid container, which can preferably be replaceably arranged in the housing. When the liquid is contained in a liquid container, for example in the form of a cartridge or an ampoule, which is replaceably accommodated in the housing, not only different liquids can be injected with one and the same device with the least possible effort, for example liquid pharmaceutical products of different types, as may be required for a series of vaccinations, by simply subsequently inserting containers with different liquids into the device one after the other. The arrangement also has the advantage that the device can be cleaned and/or sterilized particularly easily and thoroughly without the liquid supply contained in it, which is particularly important for its use in pharmaceutical areas, but also in the (commercial) cosmetic sector.

It has proven to be very advantageous when the outlet nozzle is arranged on the liquid container. This arrangement allows the type and shape of the nozzle, in particular the passage for the liquid provided therein, to be adapted in the best way possible to the specific liquid contained in the liquid container and to be injected. For example, when processing liquids of comparatively high viscosity, such as hyaluronic acid products used in cosmetic applications, e.g. for wrinkle injection or lip modelling, and in medicine for injection into joints damaged by arthrosis, it may be necessary to provide a nozzle with a larger passage cross-section than for injecting simple physiological saline solution. The arrangement of the outlet nozzle directly on the liquid container then ensures that the appropriate outlet nozzle for the respective liquid absorbed in the container is used in any case. For reasons of hygiene in particular, it is preferred that the liquid containers used in the injection device according to the invention, especially those with outlet nozzles arranged thereon, are disposable containers which are disposed of after a single use, i.e. are not refilled.

The outlet nozzle can have a nozzle outlet running essentially coaxial to the housing axis of the housing. The liquid then exits in a direction coaxial with the housing axis of the housing and thus generally perpendicular to the surface of the substrate, because the housing is generally oriented perpendicular to the substrate surface, for example a skin surface, when the device is handled. However, it is also possible, in a particularly advantageous manner, for the outlet nozzle to have a nozzle outlet which runs at an angle to the housing axis, the angle preferably being greater than 45°. It is particularly advantageous if the nozzle outlet runs in a direction which is in the range of more than 75° up to or more than a right angle, i.e. the outlet direction runs essentially in a plane normal to the housing axis of the housing. When the orientation of the housing is substantially constant, i.e. approximately perpendicular to the substrate surface, this embodiment of the invention allows the liquid to be injected into the substrate substantially parallel to the substrate surface and closely below it, which is particularly easy to achieve, when the substrate, such as the skin of a human being, is pliable in its upper layer and can be depressed a certain distance in a trough-like manner by means of the device so that the nozzle outlet is then located in this trough-like forming depression below the level of the adjacent substrate and then the liquid can be injected substantially parallel to the substrate surface below this substrate surface. In particular for such an outlet nozzle, it or the front end of the housing may be provided with a depth indicator or a depth stop so that the liquid can be injected to the exact depth required below the substrate surface.

In a particularly advantageous embodiment of the invention, it is provided that the liquid container with the liquid contained therein together with an ejector plunger of the ejector device is movably accommodated in the housing or an acceleration section provided in the housing, respectively, and that the housing has at its front outlet end a stop for the liquid container. This embodiment has the advantage that the liquid container together with the liquid contained therein is first accelerated together with the ejector device in the housing before the liquid is ejected from its container through the outlet nozzle. This limits the pressure increase (static pressure increase) in the liquid when actuating the ejector device to eject the liquid by first imposing a dynamic pressure component on the liquid. Especially in the case of pressure-sensitive liquids, this can reduce or completely avoid the risk of damage. In order to slow down the (static) pressure increase in the liquid when the liquid container hits the stop, it is advantageous when a stop damper, for example an elastomeric buffer element, is provided between the stop and the liquid container.

The invention proposes a liquid container for use in carrying out the method according to the invention and/or in the device according to the invention, which is characterized by at least one accommodating space for liquid, a liquid outlet and a shock inducer element for inducing an impulse shock into the liquid accommodated in the accommodating space. The shock inducer element, which in general can be any kind of means or design of the liquid container, which makes it possible to introduce a pressure shock (impulse shock) into the liquid accommodated in the liquid container, can be acted upon by an actuating means, in particular the already mentioned ejector plunger, of the ejector device provided for this purpose, which actuating means is accelerated to high velocity after the device is triggered. When the actuating means hits the shock element of the liquid container, or when the liquid container hits the stop provided for this purpose in the housing in the case of the embodiment in which the actuating means is accelerated together with the liquid contained therein and the ejector plunger jointly to a velocity, the shock impulse inherent in the actuating means due to its mass and its high velocity is transferred to the liquid contained in the container and causes a sudden, very large increase of pressure (pressure surge) in the liquid, which results in a first partial quantity of the liquid contained in the container being pressed through the outlet nozzle at a correspondingly high pressure, wherein preferably a rotational movement is applied to the liquid as it passes through the nozzle passage. The first partial quantity discharged as a result of the pressure shock thus exits the outlet nozzle corresponding to the very high pressure rapidly generated in the liquid at very high velocity as a liquid jet (preferably) rotating around its jet axis and penetrates the substrate without any further significant resistance. In the substrate, the rotating liquid jet creates an injection channel which is open at the substrate surface and reaches an injection depth. This achieved depth depends essentially on the jet thickness, which is essentially determined by the cross-section of the outlet nozzle through which the liquid leaves the device, and on the jet velocity at which the first partial quantity impinges on the substrate surface. This velocity, in turn, is (among others) a function of the pressure that is actually attained for only a very short time as a result of the impulse shock in the liquid. By varying the velocity of the actuating means (ejector plunger) and thus the amount of the impulse given to it, the injection or penetration depth into the substrate can be adjusted. Surprisingly, it has been found that a second partial quantity of liquid subsequently introduced into the substrate through the injection channel previously created by means of the first partial quantity, which second partial quantity is then usually ejected through the outlet nozzle at significantly lower pressure and injected into the substrate at a correspondingly low velocity, also reaches the end of the previously created injection channel, i.e. the penetration depth, and is then distributed in this depth essentially evenly around the channel. A second partial quantity of liquid can thus be injected to the desired depth in the manner of a liquid depot. For carrying out such a two- or multi-stage injection, an ejector device with electromagnetic drive for the ejector plunger has proved particularly suitable. The ejector plunger is first accelerated by the electromagnetic drive in an acceleration section in front of the liquid container (or together with it) to the desired high plunger velocity and then in a very brief time interval, preferably abruptly, decelerated (optionally together with the liquid container) to generate the impulse shock in the liquid, whereupon the pressure in the liquid suddenly rises to a very high value as described and the first partial quantity of liquid is ejected from the container and leaves the outlet nozzle at a very high velocity, preferably under rotation, i.e. a helical movement. For ejecting a second (and possible further) partial quantity(ies) into the injection channel thus created by means of the first partial quantity, the ejector plunger is inserted by means of the electromagnetic drive in the manner of a syringe plunger of an injection syringe with an ejection force at the shock inducer element into the volume of the liquid contained in the container and thereby expels the liquid through the outlet nozzle, from where it enters the injection channel previously shot into the substrate by the first partial quantity.

The ejector device with electromagnetic drive, which has its independent inventive merit and which is of course also suitable for methods and devices in which the liquid accelerated into the form of a thin jet for needleless injection is not set in rotation or helical movement, not only allows the above-mentioned step-wise injection with two or more partial quantities of liquid. It is also ideally suited for placing a series of injections in a short time sequence at different, preferably immediately adjacent points in the substrate. For this purpose, the ejector plunger is moved back into its initial position immediately after the generation of the impulse shock in the liquid supply, preferably by briefly reversing the direction of the current in the coil, and is thus ready for a further injection within a very short time, for which it is accelerated again in the injection direction by means of the electromagnetic coil and again generates a pressure shock in the liquid supply. A liquid container forming a cylinder space with a liquid outlet provided on a side and a piston actuatable by the ejector plunger, which piston is insertable into the cylinder space in steps effected by the plunger hitting it, in order to always eject a partial quantity of liquid from the liquid outlet, which liquid then exits the device through the outlet nozzle, is particularly suitable for carrying out such series injections. As the piston is pushed increasingly deeply into the cylinder space of the liquid container by the ejector plunger with each injection step, the acceleration section available to the ejector plunger between a rear, constant stop in the housing and its stop at the front, defined by the piston, is step-wise increased. Since the increase of the acceleration section with otherwise unchanged general conditions, in particular constant electric current applied to the electromagnetic drive, would result in an increasingly greater velocity of the plunger when it hits the piston, the pressure shock generated in the liquid and the resulting jet velocity and penetration depth would then also increase, means are preferably provided for adapting the velocity of the plunger when it hits the piston, which means make it possible, irrespective of the position of the piston in the liquid container, to repeatedly generate in the latter at least approximately equally strong pressure pulses, so that the injections generated in series each penetrate the substrate to the same depth. The device according to the invention is thus advantageously suited for injecting under wrinkles in the skin of a patient or for producing tattoos which can be produced needle-free with the invention.

It is also possible that the electromagnet and/or the energy storage (battery/accumulator) intended for its operation are located on the moving part of the ejector device, i.e. in particular the ejector plunger, and can be removed from the housing together with it, e.g. in order to clean and/or sterilize the housing before using the device again.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Further features and advantages of the invention result from the following description and figure, in which preferred embodiments of the invention are presented and explained in more detail by means of examples. These show:

FIG. 1 a general representation of an injection device according to the invention in perspective view;

FIG. 2a-c the handling part of the injection device according to FIG. 1 in longitudinal section in different operating positions of the ejector device;

FIG. 3 the ejector device with a first version of an outlet nozzle used in the invention, in longitudinal section;

FIG. 4 a second embodiment of an outlet nozzle for use with the device according to the invention in section;

FIG. 5 a third embodiment of an outlet nozzle for use with the device according to the invention in section;

FIG. 6 a fourth embodiment of an outlet nozzle for use with the device according to the invention in section;

FIG. 7 the orifice plates of the orifice plate stack used in the embodiment according to FIG. 6 in a perspective, expanded representation (exploded view); and

FIG. 8 a fifth embodiment of an outlet nozzle for use with the device according to the invention in section.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

In FIG. 1, 10 refers to an injection device as a whole according to the invention, which has a handling part 11, which is connected via a cable connection 12 to an external power supply 13, a battery pack in the embodiment shown.

The handling part 11 of the injection device 10 can be conveniently handled by its user with a single hand. The more detailed structure of the handling part 11 is clearly visible in the sectional view according to FIG. 2a to c. Accordingly, it has a housing 14 which is provided with a recess 15 on its outer circumference in which a magnetic coil 16 is accommodated. The magnetic coil 16 is protected by a circumferential cover 17.

The magnetic coil 16 is part of an ejector device referred to as 18 in its entirety, which further comprises an ejector tube 19 made of plastic material inserted into the housing and passing through it essentially from its rear end (right in the figure) to the front (left) outlet end, and an ejector plunger 20 guided therein in a longitudinally displaceable manner, which in the embodiment shown has a rear section 21 and a front section 22. While the rear section with a larger diameter is adapted to the internal cross-section of the ejector tube 19 and can slide in it with as little play and friction as possible, the front section 22 has a smaller diameter. It forms a pressure piece 23 which can be inserted or is insertable from behind into a cylindrical liquid container 24 in the form of a liquid round or cartridge containing a liquid 25 to be injected into a substrate, for example into or under the skin of a human or animal. This liquid container 24, similar to the rear section 21 of the ejector plunger 20, is accommodated in the ejector tube 19 substantially without play, so that it can also slide easily in the latter. At the rear (i.e. on the right in the figure), the liquid container 24 is closed by a piston 26, which holds the liquid 25 in the container 24 and is pushed into the cylinder space 27 defined by the container 24 to such an extent that the pressure piece 23 also fits a little into this cylinder space at its rear. On its left outlet side, as shown in the figure, the liquid container 24 is closed with a membrane 28.

The ejector tube 19 is fitted with a cap 29 at its front end, left-hand side in FIG. 2, which has a central opening in which a piercing cannula 30 projecting inwards towards the liquid container 24 is accommodated. An elastic buffer element 31 surrounding the piercing cannula 30 is arranged inside the cap.

The piercing cannula 30 protrudes with its outlet side end opposite its piercing tip 32 somewhat beyond the cap 30 and thus forms a centering for an outlet nozzle 33, which is fitted onto this outlet side end of the cannula 31 and fixed to the housing 14 by means of a union nut 34.

In order to prepare the device for use, the ejector plunger 20 with its front section 22, which forms the pressure piece 23, is first inserted from behind into the cartridge-like liquid container 24, wherein the front side of the pressure piece 23 contacts the piston 26 in the cylindrical opening of the liquid container. This assembly of liquid cartridge and ejector plunger can then be inserted with the membrane 28 in front, which closes the liquid cartridge at the front, from behind into the ejector tube 19 in the housing 16, for which purpose a cover cap 35 arranged at the rear of the housing can be opened. After closing the cover cap the device is ready for operation. This operating state is shown in FIG. 2 a.

Based on the FIGS. 2a to 2c , the operation of the device according to the invention can be easily understood during injection: FIG. 2a shows the initial position of the ejector device, in which the rear section 21 of the ejector plunger 20 is in the rearmost position (in the figure on the right) (rear end position). The free space in the ejector tube 19 which extends in this position of the ejector plunger and the liquid container placed on the front of the ejector plunger up to the end cap 29 forms an acceleration section S, over the length of which the assembly consisting of plunger and liquid container 24 can be accelerated. In order to trigger an injection from the position shown in FIG. 2a , the magnetic coil 16 is supplied with electric energy from the battery pack 13 and thereby accelerates the ejector plunger 20 with the liquid cartridge 24 attached to the front of it over the acceleration section S in a direction of movement towards the outlet nozzle (to the left in the figure). The accelerated assembly reaches a very high velocity in a very short time, which in practice can be over 500 m/s, and even over 800 m/s with a suitably longer acceleration section. The liquid container 24 with the liquid 25 contained in it first follows this movement until it is decelerated by the buffer element 31, which is compressed between the front cap 29 of the ejector tube 19 and the assembly of ejector plunger 20 and liquid container 24 moved at high velocity by the magnetic coil 16 towards the outlet nozzle 33. The main purpose of the buffer element 31 is to prevent the liquid container striking against the front cap 29 from jumping back from it. The position of the ejector device in this operating state is shown in FIG. 2 b.

As is only schematically indicated by dotted lines in the illustration according to FIG. 2a , the free space 36, which is present inside the ejector tube 19 between its front cap 29 and the front end of the liquid container 24 closed by the membrane, is connected to the space 38 behind the rear plunger end 21 by means of an overflow line 37. Through the overflow line, air can be displaced from the front free space 36 or actually actively sucked out by the negative pressure in space 38 which forms behind the plunger during its forward movement, thus ensuring that the ejector plunger 20 with the liquid container 24 is not slowed down due to increased air resistance. In the practical implementation of this feature, the overflow line can be integrated into the wall of the housing so that it is actually not noticeable from the outside.

As soon as the piercing tip 32 of the piercing cannula 30 pierces the membrane 28 provided at the front end of the liquid container 24, the liquid 25 contained in the container can emerge from the front end of the container and pass through the cannula 31 into the outlet nozzle 33. Since at the moment of piercing, the liquid container 24 with the liquid 25 contained in it is still moving at high velocity and this movement stops very abruptly as soon as the buffer element 29 is compressed as much as possible, there is a brief strong pressure increase in the liquid volume contained in container 24 (pressure shock), because the ejector plunger 20 pressing on the rear of piston 26 in the liquid container 24 with its pressure piece 23 is decelerated just as suddenly and transmits its own dynamic energy as an impulse shock into the initially co-accelerated liquid, which triggers the strong pressure increase in the latter. Due to this briefly, very high pressure in the liquid, a first partial quantity of the liquid is pushed at a correspondingly high pressure through the cannula and the subsequent outlet nozzle 33 and exits the outlet nozzle at the outlet side of the outlet nozzle at a high orifice velocity corresponding to the high static pressure, ambient pressure being imposed on the liquid at the outlet side of the outlet nozzle and the inherent pressure energy being converted into kinetic energy (velocity). In practice, the outlet nozzle used, which is preferably designed as described below, can have a passage 36 for liquid 25 with a diameter of 80 to 300 μm, so that the first partial quantity of liquid ejected as a result of the impulse shock impinges as a very fine liquid jet with a correspondingly small cross-section on the substrate at a very high velocity. The exit velocity of the liquid as a result of the pressure shock can easily reach 1000 m/s. With this extremely fast and thin liquid jet, an injection channel is created (shot) in the substrate to a depth that depends on the jet velocity and its diameter and thus ultimately on the strength of the impulse shock generated by the ejector plunger in the liquid supply.

According to the invention, it is possible to inject the entire amount of liquid contained in the liquid container or, anyway, a second partial quantity of liquid in addition to the first partial quantity injected forming an injection channel, as explained above, into the substrate at this injection point. For this purpose, the magnetic coil 16 can continue to be powered after reaching the front end position of the liquid container 24 (FIG. 2b ). This causes the ejector plunger 20 with its front section 22 (pressure piece 23) to be pressed further from behind against the piston 26 in the liquid container so that at least a part of the liquid (second partial quantity) still remaining in the container after the pressure shock has decayed is pressed through the cannula 31 as with a conventional syringe and then ejected through the outlet nozzle 33. Surprisingly, it has been found that despite the significantly lower pressure with which the second partial quantity is then ejected and the lower exit speed of the second partial quantity liquid from the outlet nozzle resulting therefrom, also the second partial quantity reliably and completely penetrates into the injection channel created in the substrate previously by means of the first partial quantity and thus reaches into the substrate, i.e. in the embodiment into or under the skin. This generally leads to a depot formation at the end of the injection channel, i.e. the second partial quantity of liquid is distributed substantially evenly in the tissue in a spherical shape around the end of the injection channel. The injection can be continued until plunger 26 is fully inserted from pressure piece 23 to the front end of the liquid container (FIG. 2c ).

If desired, a sequence of more or less closely positioned injections of comparatively small amounts of liquid can be made at short intervals with the device. For this purpose, the ejector plunger 20 is pulled back into its initial position (i.e. to the right in the figure) by suitable control (changing the direction of electrical current) of the magnetic coil 16 directly after generating a pulse shock in the liquid contained in the container. Since the liquid container 24 for the embodiment described here is already open from the piercing tip 32 of the cannula 30 at the membrane after the very first injection carried out as described above, in this mode of operation it remains expediently in its left-hand end position as shown in the figure according to FIG. 2c , which can be ensured by a suitable retaining element not shown. For example, for this purpose, a locking bar pretensioned radially inwards transversely to the longitudinal axis of the ejector tube 19 by means of a spring can be accommodated in a recess in the ejector tube, which locking bar, after the liquid cartridge has passed after the first injection has been triggered, moves radially inwards under the spring pressure, gripping behind the rear edge (in the figure at the right end of the liquid container) of the liquid container and thus preventing it from moving back again. The ejector plunger 20, which has been pulled back again by momentarily reversing the polarity of the magnetic coil, can be held in its retracted position by means of a small permanent magnet or an electromagnet on the rear cover cap 35 of the housing so that it does not drop again unintentionally and/or prematurely against the shock inducer element (piston 26) on the liquid container solely due to its own weight. The ejector plunger can then, optionally by overcoming the magnetic holding force of the aforementioned (not shown) permanent magnet or electromagnet, be accelerated again to high velocity via the acceleration section lying in front of it, wherein it slides to the end of its movement with the front pressure piece back into the cylinder space at the rear end of the liquid container and there hits the piston 26 and thus again generates a pressure shock for ejecting a further (small) partial quantity of liquid. The repeated triggering of the electromagnet and the resulting ejection of liquid from the device (after its repositioning at the next, desired injection point) can be done manually, i.e. by actuating a (not shown) triggering mechanism, or automatically at pre-determined time intervals, which can also be very short, for example when using the device as a tattoo machine. An operation of the device with a triggering frequency in the range of 35 to 200 Hz is easily possible with suitable dimensioning of the plunger and the acceleration section.

In FIG. 3, a first preferred embodiment of the outlet nozzle 33 to be used is shown in its mounted state on the housing of the device according to the invention. It can be seen that this outlet nozzle 33 has a central passage 39, running coaxially to the cannula 30, for the liquid 25 to be injected, which passage has on its passage wall 40 at least one screw-shaped or helical fluid channel 41, which extends from the nozzle inlet 42 on the side of the cannula 30 to the nozzle outlet 43, from which the liquid 25 exits for injection. This helical fluid channel 41 causes a swirl or rotational movement to be imposed on the liquid flowing through the outlet nozzle 33 so that the liquid jet 44 is set in rotation around its jet axis 45 when it exits the nozzle and thus impinges on the substrate 46, in the embodiment the skin of a human or animal, as a rotating liquid jet.

The superposition of the translatory movement of the liquid with the rotation imposed on it causes the liquid jet 44 to practically screw or drill itself into the substrate 46 when it impinges on the substrate, wherein the helical movement of the liquid apparently holds the jet together, so that when the liquid impinges on the surface of the skin or substrate, it does not mushroom and splash off sideways, but rather enters the substrate with as little loss as possible and creates an injection channel 47 with a depth T, which depends essentially on the nature of the substrate, the velocity of the liquid jet in the axial direction and its cross-section. In the embodiment shown, the passage 39 in the outlet nozzle has a diameter of approx. 80 to 100 μm on the outlet side and the (first) partial flow exiting this passage as a result of the pressure shock in the liquid supply exits the nozzle at a velocity in the order of 100 to 1000 m/s. The depth of the resulting injection channel in (human or animal) tissue can thus be adjusted between a few millimetres and a few centimetres.

FIG. 4 shows a further embodiment of an outlet nozzle according to the invention, wherein corresponding features are provided with the same reference signs as for the first embodiment. The outlet nozzle 33 shown in FIG. 4 is fixed to the housing by means of a union nut 34 a, which also forms a spacer or depth gauge. The outlet nozzle shown in FIG. 4 can be pressed a little bit into the substrate 46, namely from its upper side 48 into the skin of a patient, so that it forms a trough-like depression 49 therein. A radially outwardly projecting ring area 50 on the union nut 34 a limits the depth of depression of the nozzle or indicates when a desired depth has been reached, which is the case when the outer edge of the ring area 50 also comes into contact with the skin surface 48. The outlet nozzle 33 has a passage 39 with an approximately cup-shaped nozzle chamber 51 on the inlet side, on the wall of which two (or more) fluid channels 41 are formed, which wrap around each other helically in the manner of a double (or multiple) helix and which, as described, impose the swirl (spiral movement) according to the invention on the liquid flowing through the nozzle. The nozzle has two (or also several) laterally e.g. radially outwardly open nozzle outlets 43, through which, in contrast to the first embodiment of the device, jets of liquid 44 do not leave the nozzle coaxially to its longitudinal direction, but in directions which are essentially perpendicular to the longitudinal axis of the device or—in the embodiment shown—even an angle α, which can be slightly greater than 90°. In this way it is easily possible to inject the liquid not perpendicularly to the substrate surface, but to distribute it under the uppermost skin layer 52 essentially parallel to the surface in the substrate.

The embodiment of an outlet nozzle 33 shown in FIG. 5 largely corresponds to that shown in FIG. 3. However, the passage 39 here does not have a constant cross-section over its entire length, but on the inlet side it initially has a converging section 53, whose cross-section decreases in the flow direction 54 of the liquid 25 ejected through the nozzle, and then continues into a section of constant cross-section 55. In both sections 53 and 55, helically spiraling fluid channels 41 are provided on their walls, in the embodiment shown two channels, which are arranged in the manner of a double helix. The converging section firstly ensures an acceleration of the fluid passing from the fluid container into the nozzle.

FIG. 6 shows an embodiment of the outlet nozzle for the invention, in which the or a fluid channel 41 extends through the outlet nozzle 33 in the form of a helical pipe 56 from the inlet side 42 to the outlet side 43 of the outlet nozzle 33. The arrangement is such that the pipe 56 has a helical radius R decreasing from the inlet side 42 to the outlet side 43. Thereby a cyclone effect is achieved, i.e. an acceleration of the rotational velocity of the liquid flowing through the pipe helix 56 around itself, so that the liquid rotates around itself at high velocity when it exits the nozzle outlet.

In the embodiment shown in FIGS. 7 and 8, the outlet nozzle 33 has a plurality of orifice plates 58 which are arranged one behind the other in the direction of passage 54 of the liquid in the form of an orifice plate stack 57, which orifice plates each have a slot opening 59 extending over a part of the plate diameter d, the slot openings 59 of successive orifice plates 58 in the orifice plate stack 57 being arranged offset to one another in the circumferential direction by an angular amount β. The amount of this angular offset β in the circumferential direction is smaller at the radially outer ends of the slot openings 59 than the width of the slot openings. This results in a spiral staircase-like fluid channel 41 with a central passage opening. The embodiment with the stacked orifice plates can be manufactured particularly easily and cost-effectively, even having the smallest dimensions with an aperture cross section in the micrometer range.

In the outlet nozzle 33 shown in FIG. 8, four fluid channels 41 are formed on the wall 40 of the passage 39 passing through it, which run in a straight line parallel to the flow direction over the length of the section with constant cross-section 55 and are separated from each other by webs 60. In this embodiment, the entire nozzle is rotatably mounted on the housing of the device and can be driven by an electric motor using a coil. When it is set in rotation during the ejection, the webs on the passage wall transfer this rotational movement to the outer circumferential area of the liquid jet flowing through the nozzle, thus imposing the rotational movement according to the invention on the jet.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

1.-6. (canceled)
 7. An injection device for the needleless injection of a liquid into a substrate, particularly for injection of liquid pharmaceutical or cosmetic product into a biological tissue, comprising a housing, a liquid supply accommodated or arrangeable in the housing, an outlet nozzle and an ejector device for ejecting liquid from the liquid supply through the outlet nozzle, wherein the ejector device has means for generating an impulse shock acting at least on a first quantity of liquid in the liquid supply.
 8. The device according to claim 7, wherein the means of the ejector device for generating the impulse shock comprise an ejector plunger acceleratable to an impulse velocity, with whose mass accelerated to the impulse velocity the first quantity of liquid can be acted on.
 9. The device according to claim 7, wherein the liquid supply is actable on by means of an ejector piston actuatable by the ejector device, which ejector piston in turn is actable on or formed by the ejector plunger.
 10. The device according to claim 7, wherein the ejector device has an electromagnetic drive for the ejector plunger.
 11. The device according to claim 7, wherein the ejector device has an acceleration section for the ejector plunger.
 12. The device according to claim 10, wherein the electromagnetic drive is arranged at a rear end of the housing spaced from the outlet nozzle or approximately in the middle of the housing, wherein the acceleration section extends between the outlet nozzle and the rear end of the housing.
 13. The device according to claim 10, wherein the electromagnetic drive has a magnetic coil formed on the ejector plunger itself as well as an iron cylinder and/or a stator coil surrounding the ejector plunger
 14. The device according to claim 10, wherein the ejector plunger is provided with an electric power storage device to supply the electromagnetic drive with electric power.
 15. The device according to claim 7, wherein the acceleration section in the area in front of and behind the ejector plunger is connected to pressure compensation openings.
 16. The device according to claim 15, wherein the pressure compensation openings are connected to each other via an overflow line.
 17. The device according to claim 7, wherein the ejector device comprises means for generating an increase in pressure in the liquid supply immediately following the exerted impulse shock.
 18. The device according to claim 17, wherein means for generating a pressure increase are substantially formed by the ejector plunger which, after exerting the impulse shock, acts on the liquid supply by means of a force-exerting drive.
 19. The device according to claim 18, wherein the force-exerting drive is the electromagnetic drive.
 20. The device according to claim 7, wherein the liquid supply is accommodated in a liquid container which can be arranged replaceably in the housing.
 21. The device according to claim 20, wherein the outlet nozzle is arranged on the liquid container.
 22. The device according to claim 8, wherein the outlet nozzle comprises means for setting the liquid jet at least in its outer area in rotation before its impingement on the substrate.
 23. The device according to claim 7, wherein the outlet nozzle has a nozzle outlet running substantially coaxial to the housing axis of the housing.
 24. The device according to claim 7, wherein the outlet nozzle has a nozzle outlet running substantially in a plane normal to the housing axis of the housing.
 25. The device according to claim 7, wherein the outlet nozzle and/or the front end of the housing is/are provided with a depth indicator or a depth stop.
 26. The device according to claim 7, wherein the liquid container with the liquid contained therein together with the ejector plunger is movably accommodated or accommodatable in the housing or an acceleration section provided in the housing, respectively, and that the housing has at its front outlet end a stop for the liquid container. 27.-28. (canceled) 